Fluid coupling

ABSTRACT

A pulsation absorber is provided in a fluid channel formed in a body of a fluid coupling. Fluid flows through the fluid channel in an assembled state. The pulsation absorber is arranged to deform in a same direction as the fluid to flow in the fluid channel pulsates. The pulsation absorber thereby absorbs pulsation of the fluid.

BACKGROUND OF THE INVENTION

The present invention generally relates to a fluid coupling, and moreparticularly, to a fluid coupling for use in a fuel supply system of avehicle.

Japanese Patent Application Publication No. H09(1997)-195885 discloses afuel supply system of a fuel returnless type.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a fluid couplingcapable of damping pulsation of fluid effectively, while using a limitedspace and being small in size and low in cost.

According to one aspect of the present invention, a fluid couplingincludes: a body formed with a fluid channel; and a pulsation absorberprovided in the fluid channel, and arranged to deform in a samedirection as fluid to flow in the fluid channel pulsates, and thereby toabsorb pulsation of the fluid.

The other objects and features of this invention will become understoodfrom the following description with reference to the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing a fluid coupling according to anembodiment of the present invention.

FIG. 2 is a sectional view showing a fluid coupling according to anotherembodiment of the present invention.

FIG. 3 is a sectional view showing a pulsation absorber applicable tothe fluid coupling, according to still another embodiment of the presentinvention.

FIG. 4 is a sectional view showing a pulsation absorber applicable tothe fluid coupling, according to still another embodiment of the presentinvention.

FIG. 5 is a sectional view showing a pulsation absorber applicable tothe fluid coupling, according to still another embodiment of the presentinvention.

FIG. 6 is a sectional view showing a pulsation absorber applicable tothe fluid coupling, according to still another embodiment of the presentinvention.

FIG. 7 is a sectional view showing a pulsation absorber applicable tothe fluid coupling, according to still another embodiment of the presentinvention.

FIG. 8 is a sectional view showing a fluid coupling according to stillanother embodiment of the present invention.

FIG. 9 is a sectional view showing a pulsation absorber applicable tothe fluid coupling of FIG. 8, according to still another embodiment ofthe present invention.

FIG. 10 is a diagram showing a fuel supply system of a return type.

FIG. 11 is a diagram showing a fuel supply system of a returnless(non-return) type.

DETAILED DESCRIPTION OF THE INVENTION

First, in order to facilitate understanding of the present invention, adescription will be given of fuel supply systems for a vehicle. FIG. 10is a diagram showing a fuel supply system of a return type. In this fuelsupply system, fuel is supplied from a fuel tank (not shown in FIG. 10)via an underfloor supply line 101 and a supply tube 102 to a deliverypipe 103. Then, the fuel is supplied from delivery pipe 103 to fuelinjectors 104 of each cylinder. Delivery pipe 103 is equipped with apressure regulator 105. Pressure regulator 105 maintains constantpressure in delivery pipe 103 by returning surplus fuel via a returntube 106 and an underfloor return line 107 to the fuel tank.

FIG. 11 is a diagram showing a fuel supply system of a returnless(non-return) type. In this fuel supply system, fuel is supplied from afuel tank (not shown in FIG. 11) via underfloor supply line 101 andsupply tube 102 to delivery pipe 103. Then, the fuel is supplied fromdelivery pipe 103 to fuel injectors 104. Delivery pipe 103 is equippedwith a pulsation damper 108. Pulsation damper 108 damps pulsation, andnoise of pulsation, of the fuel which originate from a dischargingaction of a fuel pump or a fuel injection action of fuel injectors 104.

In the fuel supply system of FIG. 10, fluid couplings or quickconnectors 110 are each provided between supply line 101 and supply tube102, between supply tube 102 and delivery pipe 103, between pressureregulator 105 and return tube 106, and between return tube 106 andreturn line 107. In the fuel supply system of FIG. 11, fluid couplings110 are each provided between supply line 101 and supply tube 102, andbetween supply tube 102 and delivery pipe 103. Generally, each of fluidcouplings 110, straight type or elbow type, is made of metal and/orresin, and includes one or two O rings in a joining portion.

Recently, improvements have been required for vehicles to be reducedfurther in weight and cost. Therefore, such vehicles have employed anincreasing number of fuel supply systems of the returnless type whichhas a smaller number of elements than the return type.

However, in the fuel supply system of the returnless type, pulsation ofthe fuel is likely to occur on the part of delivery pipe 103, comparedwith the return type. For this reason, delivery pipe 103 of thereturnless type is equipped with pulsation damper 108. Therefore, thefuel supply system of the returnless type requires an attaching portion,such as a flange, for joining pulsation damper 108 to delivery pipe 103,and an arrangement for sealing the joining part. Thus, the fuel supplysystem of the returnless type may have a complex structure, and cannoteasily be reduced in cost. Besides, such fuel supply system of thereturnless type cannot easily be laid out in a small space in an engineroom.

FIG. 1 is a sectional view showing a fluid coupling A1 according to anembodiment of the present invention. Each of fluid couplings (or quickconnectors) of the following embodiments is applicable to joint betweensupply tube 102 (a resin tube T) and delivery pipe 103 (a metal pipe P)in the fuel supply system of the returnless type of FIG. 11. However,the fluid couplings are not limited to the following embodiments inpositioning and detailed structure, and may be applicable asmodifications and variations of such embodiments.

Fluid coupling A1 of FIG. 1 is a straight type, and includes one orfirst joining portion J1, and the other or second joining portion J2provided integrally with first joining portion J1. First joining portionJ1 and second joining portion J2 form a body of fluid coupling A1. Firstjoining portion J1 includes two O rings 1 and a back-up ring 2. O rings1 and back-up ring 2 are attached to an inside surface of first joiningportion J1. Second joining portion J2 includes a projecting portion 3.Projecting portion 3 for retaining a tube is formed on an outercircumference of second joining portion J2. Metal pipe P (delivery pipe)and resin tube T (supply tube) are connected with first joining portionJ1 and second joining portion J2, respectively, in an assembled state.Specifically, metal pipe P together with a spacer 4 is fit into firstjoining portion J1, and resin tube T is fit over second joining portionJ2. Fuel which is fluid flows through fluid coupling A1 in the assembledstate.

The body of fluid coupling A1 is formed by material resistant to fuel.In this example, the body of fluid coupling A1 is formed by materialcomposed mainly of a resin selected from a group consisting ofpolyamide, polyolefin, polysulfide, fluorocarbon resin, polyester,polyacetal and polyketone.

The body of fluid coupling A1 is formed with a fluid channel 5 extendingthrough the body of fluid coupling A1. Fluid coupling A1 includes asupport 6, and a pulsation absorber provided in fluid channel 5. Thepulsation absorber of this embodiment is a bellows 7. Specifically,support 6 is fixed in fluid channel 5, and bellows 7 is supported bysupport 6. Pulsation absorber or bellows 7 is arranged to deform in asame direction as fluid to flow in fluid channel 5 pulsates, and therebyabsorb the pulsation of the fluid. A part or first part of fluid channel5 at which bellows 7 is provided has a section smaller than a section ofother part or second part of fluid channel 5.

Support 6 is formed by material of the same kind as the material formingthe body of fluid coupling A1. In this example, support 6 is formed bymaterial composed mainly of glass fiber reinforced polyamide 12. Support6 is formed with at least one opening to pass the fluid through theopening. Support 6 is fixed to the body of fluid coupling A1 by rotarywelding.

Bellows 7 is formed by resin or rubber. In this example, bellows 7 isformed by polyamide 12, and molded by blow molding. Bellows 7 is joinedto support 6 air-tightly by welding, and is arranged to act as an airspring. Besides the above-mentioned polyamide 12, bellows 7 may beformed by a thermoplastic resin, such as a polyamide-based thermoplasticresin, a polyolefin-based thermoplastic resin, a fluorocarbon-basedthermoplastic resin, a polyester-based thermoplastic resin, or apolysulfide-based thermoplastic resin. Bellows 7 may also be formed by athermoplastic elastomer, or a rubber, such as a fluorocarbon-basedrubber, a nitrile-based rubber, or an acrylic-based rubber.

In fluid coupling A1 of this embodiment, pulsation absorber or bellows 7is provided in fluid channel 5, and is arranged to deform in the samedirection as the pulsation of the fluid to flow in fluid channel 5, andthereby absorb the pulsation of the fluid effectively. Thus, pulsationabsorber or bellows 7 confronts a propagation direction of the pulsationof the fluid, in an assembled state in the fuel supply system or fluiddelivery system. Specifically, in the fuel supply system, when the fuelis supplied from the fuel tank to metal pipe P, and pulsation of thefuel originating from the fuel injection action of fuel injectors 104occurs on the part of metal pipe P, bellows 7 confronting thepropagation direction of the pulsation deforms springily or elastically,or expand and contract, to absorb the pulsation of the fuel effectively.

Thus, fluid coupling A1 of this embodiment includes pulsation absorberor bellows 7 provided in fluid channel 5. Hence, fluid coupling A1 ofthis embodiment does not require an additional space for a pulsationabsorber. In fluid channel 5, pulsation absorber or bellows 7 isarranged to act as air spring. Therefore, fluid coupling A1 has a simplestructure having a small size and a small number of elements, and iscapable of damping the pulsation of the fluid occurring in the fuelsupply system. With fluid coupling A1 of this embodiment, the fuelsupply system of the returnless type of FIG. 11 can have a structurewithout pulsation damper 108, and thus can be reduced in weight andcost, and can be easily laid out in a limited space in an engine room.

Besides, pulsation absorber or bellows 7 of fluid coupling A1 of thisembodiment is formed by resin or rubber. Thus, bellows 7 is light inweight and low in cost, and has a property of deforming efficiently toabsorb the pulsation of the fluid effectively. Additionally, since resinor rubber exhibits an excellent formability, bellows 7 can be formedeasily to have a desired spring constant.

Further, support 6 of fluid coupling A1 of this embodiment is fixed tothe body of fluid coupling A1 by rotary welding, and bellows 7 is joinedto support 6 by welding. Thus, these elements can be joined to oneanother easily and securely without using joining parts. Therefore, thestructure of fluid coupling A1 can be further simplified and reduced inweight.

Besides, fluid coupling A1 of this embodiment may be applicable betweensupply line 101 and supply tube 102 in the fuel supply system of thereturnless type of FIG. 11. In this case, supply line 101 may beconnected with first joining portion J1, and bellows 7 can absorbpulsation of the fuel which originates from the discharging action ofthe fuel pump.

Further, fluid coupling A1 of this embodiment is formed with fluidchannel 5, and the section of the part of fluid channel 5 at whichbellows 7 is provided is smaller than the section of the other part offluid channel 5. The thus-narrowed part of fluid channel 5 acts as anorifice, and thereby is capable of reducing the propagation of thepulsation of the fuel.

FIG. 2 is a sectional view showing a fluid coupling A2 according toanother embodiment of the present invention. Elements in FIG. 2 that areidentical or equivalent to the elements shown in FIG. 1 are indicated bythe same reference marks, and may not be described in detail in thispart of description.

Fluid coupling A2 of FIG. 2 is an elbow type, and includes first joiningportion J1, and second joining portion J2 provided integrally with firstjoining portion J1. Second joining portion J2 is arranged substantiallyorthogonal to first joining portion J1 so that first joining portion J1and second joining portion J2 form an elbow portion. Fluid coupling A2also includes an extension portion E extending from the elbow portioncoaxially with first joining portion J1. Extension portion E has an openend opening in the coaxial direction or opposite direction from theelbow portion, and includes a support 11, and a pulsation absorberarranged to absorb pulsation of fluid to flow in fluid channel 5 in anassembled state.

Support 11 of this embodiment is a plate member formed by glass fiberreinforced polyamide 12. The pulsation absorber of this embodiment isattached to support 11, and support 11 is fixed to the open end ofextension portion E by rotary welding so as to block up the open end ofextension portion E.

The pulsation absorber of this embodiment includes bellows 7 and anelastic member. Bellows 7 of this embodiment is formed by resin orrubber, as in the foregoing embodiment. The elastic member of thisembodiment is provided inside bellows 7, and is arranged to deformspringily or elastically, or expand and contract, together with bellows7. The elastic member of this embodiment is a molded member 12 formed byresin or rubber. Molded member 12 of this embodiment is made of fluororubber compression-molded in a cylindrical form, and is providedcoaxially with bellows 7.

Besides the above-mentioned fluoro rubber, molded member 12 may be madeof rubber of various types, such as nitrile rubber, acrylic rubber,silicone rubber, fluorinated silicone rubber, hydrin rubber, urethanerubber, ethylene-propylene rubber, or butyl rubber. Molded member 12 mayalso be made of resin of various types, such as polyolefin, polysulfide,fluorocarbon resin, polyester, polyacetal, polyketone, polyvinylchloride, or thermoplastic elastomer.

Thus, in fluid coupling A2 of this embodiment, the pulsation absorber iscomposed of bellows 7 and molded member 12 arranged to act respectivelyas air spring and a rubber spring by deforming springily or elastically,or expanding and contracting together. Additionally, bellows 7 andmolded member 12 each formed by resin or rubber exhibit high dampingeffects. Therefore, the pulsation absorber of this embodiment can absorbthe pulsation of the fluid highly effectively even when pressure of thefluid is relatively high.

Besides, since the pulsation absorber of this embodiment is composed ofbellows 7 and molded member 12 each formed by resin or rubber, thepulsation absorber can be formed to have a desired spring constant withan increased degree of freedom, and thereby can adapt to variousintensities of pressure and pressure pulsation in the fluid.Additionally, fluid coupling A2 of this embodiment has a simplestructure having a small size and a small number of elements, as in theforegoing embodiment, and the fuel supply system adopting fluid couplingA2 of this embodiment can be reduced in weight and cost, and can beeasily laid out in a limited space in an engine room.

FIG. 3 is a sectional view showing a pulsation absorber applicable tothe fluid coupling, according to still another embodiment of the presentinvention. The pulsation absorber of FIG. 3 includes bellows 7 and anelastic member. Bellows 7 is formed by resin or rubber. The elasticmember of this embodiment is provided inside bellows 7, and is arrangedto deform springily or elastically, or expand and contract, togetherwith bellows 7. The elastic member of this embodiment includes ahollow-molded member 13. Hollow-molded member 13 is formed by resin orrubber in a bellows form.

FIG. 4 is a sectional view showing a pulsation absorber applicable tothe fluid coupling, according to still another embodiment of the presentinvention. The pulsation absorber of FIG. 4 includes bellows 7 and anelastic member. Bellows 7 is formed by resin or rubber. The elasticmember of this embodiment is provided inside bellows 7, and is arrangedto deform springily or elastically, or expand and contract, togetherwith bellows 7. The elastic member of this embodiment includes afoam-molded member 14. Foam-molded member 14 is formed by resin orrubber containing numerous bubbles, and shaped in a cylindrical form.

FIG. 5 is a sectional view showing a pulsation absorber applicable tothe fluid coupling, according to still another embodiment of the presentinvention. The pulsation absorber of FIG. 5 includes bellows 7 and anelastic member. Bellows 7 is formed by resin or rubber. The elasticmember of this embodiment is provided inside bellows 7, and is arrangedto deform springily or elastically, or expand and contract, togetherwith bellows 7. The elastic member of this embodiment includes moldedmember 12. Molded member 12 is formed by resin or rubber in acylindrical form. Support 11 of this embodiment is formed with an airhole 11 a exposing an inside part of bellows 7 to open air. When bellows7 undergoes load of the pulsation of the fluid, bellows 7 takes air inand out of the inside part via air hole 11 a. Therefore, the pulsationabsorber of this embodiment can obtain increased damper effects.

FIG. 6 is a sectional view showing a pulsation absorber applicable tothe fluid coupling, according to still another embodiment of the presentinvention. The pulsation absorber of FIG. 6 includes bellows 7 and anelastic member. Bellows 7 is formed by resin or rubber. The elasticmember of this embodiment is provided inside bellows 7, and is arrangedto deform springily or elastically, or expand and contract, togetherwith bellows 7. The elastic member of this embodiment includes a moldedmember 15 and a coil spring 16. Molded member 15 is formed by resin orrubber in a thin cylindrical form. Coil spring 16 is disposedconcentrically outside molded member 15.

FIG. 7 is a sectional view showing a pulsation absorber applicable tothe fluid coupling, according to still another embodiment of the presentinvention. The pulsation absorber of FIG. 7 includes bellows 7 and anelastic member. Bellows 7 is formed by resin or rubber. The elasticmember of this embodiment is provided inside bellows 7, and is arrangedto deform springily or elastically, or expand and contract, togetherwith bellows 7. The elastic member of this embodiment includes acomposite-molded member 17. Composite-molded member 17 includes coilspring 16 insert-molded in resin or rubber.

The pulsation absorbers of FIGS. 3˜7 are applicable to fluid couplingsA1 and A2 of FIGS. 1 and 2, and are capable of obtain similar effectsand advantages as in the foregoing embodiments. Especially, thepulsation absorber composed of bellows 7 and at least one of the moldedmembers and the coil spring can be formed to have a desired springconstant with a further increased degree of freedom.

The pulsation absorbers of FIGS. 3 and 5˜7 may use a foam-molded memberas shown in FIG. 4 in place of each of the molded members of FIGS. 3 and5˜7. In each case, the pulsation absorbers can obtain a desired springconstant by varying foaming rates of the foam-molded member. Besides,each of the molded members may be impregnated with fluid such as oil,and thereby can be formed to have an adjusted ability to absorb thepulsation while being prevented from deterioration. Additionally, airhole 11 a of support 11 of FIG. 5 is applicable to the foregoingembodiments and the following embodiments.

FIG. 8 is a sectional view showing a fluid coupling A3 according tostill another embodiment of the present invention. Elements in FIG. 8that are identical or equivalent to the elements shown in FIGS. 1 and 2are indicated by the same reference marks, and may not be described indetail in this part of description.

Fluid coupling A3 of FIG. 8 is a straight type, and includes firstjoining portion J1, and second joining portion J2 provided integrallywith first joining portion J1. The body of fluid coupling A3 is formedintegrally with a damping chamber F. Damping chamber F is located at amiddle part of the body and branches off from fluid channel 5. Fluidcoupling A3 of this embodiment includes pulsation absorber disposed indamping chamber F, and arranged to absorb pulsation of fluid to flow influid channel 5 in an assembled state. The pulsation absorber of thisembodiment is bellows 7.

Damping chamber F communicates with fluid channel 5 via a communicatingpassage 8, and is formed with an open end opening in opposite directionfrom communicating passage 8. Communicating passage 8 is formed narrowerthan fluid channel 5, or is formed to have an internal sectional sizesmaller than fluid channel 5. Bellows 7 is attached to support 11, andsupport 11 is fixed to the open end of damping chamber F, as in theforegoing embodiment.

Thus, fluid coupling A3 of this embodiment is arranged to absorb thepulsation of the fluid effectively by bellows 7 deforming, or expandingand contracting, springily or elastically, and damping chamber F actingas a Helmholtz resonating chamber. Damping chamber F branches offperpendicularly from fluid channel 5, and pulsation absorber or bellows7 is disposed in thus-branched damping chamber F. Thus, the pulsationabsorber of this embodiment does not hamper the flow of the fluid, andtherefore can avoid pressure loss of the fluid.

Additionally, fluid coupling A3 of this embodiment has a simplestructure having a small size and a small number of elements, as in theforegoing embodiments, and the fuel supply system adopting fluidcoupling A3 of this embodiment can be reduced in weight and cost, andcan be easily laid out in a limited space in an engine room. Besides,the pulsation absorbers of FIGS. 2˜7 are applicable to fluid coupling A3of FIG. 8.

FIG. 9 is a sectional view showing a pulsation absorber applicable tofluid coupling A3 of FIG. 8, according to still another embodiment ofthe present invention. The pulsation absorber of FIG. 9 includes adiaphragm 18 and an elastic member. Diaphragm 18 is formed by resin orrubber, and is positioned to partition damping chamber F. The elasticmember of this embodiment is arranged to deform springily orelastically, or expand and contract, in conjunction with deformation ofdiaphragm 18. The elastic member of this embodiment is a coil spring 19provided between diaphragm 18 and support 11.

The fluid coupling adopting the pulsation absorber of this embodimentcan obtain similar effects and advantages as in the foregoingembodiments. The pulsation absorber of FIG. 9 is applicable to fluidcoupling A2 of FIG. 2 of the elbow type. The pulsation absorber of thisembodiment may adopt each of the elastic members of FIGS. 2˜7 in placeof coil spring 19 of FIG. 9. Diaphragm 18 and the elastic member (moldedmember) may be formed integrally from identical material by integralmolding. Thereby, the fluid coupling can have a structure with a smallnumber of elements, and can be reduced in cost.

According to another aspect of the present invention, the fluid couplingincludes: means (5) for passing fluid; and means (7; 7, 12; 7, 13; 7,14; 7, 15, 16; 7, 17, 16; 18, 19) for absorbing pulsation of the fluidby deforming in a same direction as the fluid pulsates.

This application is based on a prior Japanese Patent Application No.2004-163141 filed on Jun. 1, 2004. The entire contents of this JapanesePatent Application No. 2004-163141 are hereby incorporated by reference.

Although the invention has been described above by reference to certainembodiments of the invention, the invention is not limited to theembodiments described above. Modifications and variations of theembodiments described above will occur to those skilled in the art inlight of the above teachings. The scope of the invention is defined withreference to the following claims.

1. A fluid coupling comprising: a body formed with a fluid channel; anda pulsation absorber provided in the fluid channel, and arranged todeform in a same direction as fluid to flow in the fluid channelpulsates, and thereby to absorb pulsation of the fluid.
 2. The fluidcoupling as claimed in claim 1, wherein the pulsation absorber isprovided at a first part of the fluid channel, and the first part of thefluid channel has a section smaller than a section of a second part ofthe fluid channel.
 3. A fluid coupling comprising: a pulsation absorberprovided in a fluid channel, and arranged to absorb pulsation of fluidto flow in the fluid channel, the pulsation absorber including: abellows formed by resin or rubber; and an elastic member provided insidethe bellows, including a molded member formed by resin or rubber, andarranged to deform elastically together with the bellows.
 4. A fluidcoupling comprising: a body formed with a fluid channel of a straighttype, and a damping chamber branching off from the fluid channel; and apulsation absorber provided in the damping chamber, and arranged toabsorb pulsation of fluid to flow in the fluid channel.
 5. The fluidcoupling as claimed in claim 4, wherein the pulsation absorber includesa diaphragm formed by resin or rubber, and an elastic member arranged todeform elastically in conjunction with deformation of the diaphragm. 6.The fluid coupling as claimed in claim 1, wherein the pulsation absorberincludes a bellows formed by resin or rubber.
 7. The fluid coupling asclaimed in claim 6, wherein the pulsation absorber includes an elasticmember provided inside the bellows, and arranged to deform elasticallytogether with the bellows.
 8. The fluid coupling as claimed in claim 7,wherein the elastic member includes at least one of a molded memberformed by resin or rubber and a coil spring.
 9. The fluid coupling asclaimed in claim 3, wherein the molded member is resin or rubbercontaining numerous bubbles.
 10. The fluid coupling as claimed in claim8, further comprising a support fixed in the fluid channel, wherein thepulsation absorber is supported by the support.
 11. The fluid couplingas claimed in claim 3, wherein the fluid coupling is an elbow typeincluding an elbow portion and an extension portion extending from theelbow portion, the extension portion having an open end opening inopposite direction from the elbow portion; and the fluid couplingfurther comprises a support fixed to the open end of the extensionportion, wherein the pulsation absorber is supported by the support inthe extension portion.
 12. The fluid coupling as claimed in claim 11,wherein the support is formed with an air hole arranged to expose aninside part of the bellows to open air.
 13. The fluid coupling asclaimed in claim 3, wherein the molded member is formed in a cylindricalform, and is provided coaxially with the bellows.
 14. The fluid couplingas claimed in claim 3, wherein the molded member is a hollow-moldedmember formed in a bellows form.
 15. The fluid coupling as claimed inclaim 3, wherein the molded member is formed in a thin cylindrical form;and the elastic member further includes a coil spring disposedconcentrically outside the molded member.
 16. The fluid coupling asclaimed in claim 3, wherein the molded member is a composite-moldedmember including a coil spring insert-molded in the resin or rubberforming the molded member.
 17. A fluid coupling comprising: means forpassing fluid; and means for absorbing pulsation of the fluid bydeforming in a same direction as the fluid pulsates.